Snip
Nothing works consistently in gambling. Let's say you won 9/10 matches with single bets and your total earning is $200 from a capital of the same amount on each bet (just an example). Now given that profit won't be big with small odd single bet, the winnings could be erased with one single losing bet. High rolling amount and low rate of return and this is the opposite of accumulated bet wherein you could lose $200 on 9 bets but earning more with a in a parlay bet due to odd multiplier.
Yes you are correct we can't totally rely on any of this bet because they all work with probability and if the luck isn't there we can still find it difficult to achieve a winning even though is the smallest odd we can still lose them therefore there is no assurance in single or multiple bets.
Just that with multiple bet combination we can have a high odd with no specify winning chance and is 50/50 base game.